NCC 2022 Volume One - Building Code of Australia Class 2 to 9 buildings
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Specification 44 Calculation of heating load limit, cooling load limit and thermal energy load limit
Specification 44 Calculation of heating load limit, cooling load limit and thermal energy load limit
S44C1
Scope
New for 2022
S44C1
Scope
New for 2022
This Specification contains the method of calculating the heating load limit, cooling load limit and thermal energy load limit for compliance with J1P2 and H6P1.
To clarify the methodology for calculating the heating, cooling, and thermal energy load limits with J1P2 and H6P1.
Specification 44 provides a calculation method for the purposes of assessing compliance with J1P2 and H6P1. The load limits in Specification 44 are based on climate factors and floor area. By defining the load limits based on climate factors, cooling, heating and thermal load limit can be determined for any climate.
S44C2
Heating load limit
New for 2022
S44C2
Heating load limit
New for 2022
The heating load limit of a space, measured in MJ/m2.annum, is equal to the greater of—
- 4; and
-
, where—
- = the total annual heating degree hours of the building location; and
- = the area adjustment factor for the heating load limit, determined in accordance with Table S44C2.
Total area of habitable rooms (AH) | Area adjustment factor (FH) |
---|---|
≤ 50 m2 | 1.37 |
> 50 m2 to ≤ 350 m2 | |
> 350 m2 | 0.84 |
To detail the calculation of the heating load limit of a space.
In S44C2, the heating load limit of a space is expressed in Megajoules per square meter per annum (MJ/m2.annum). The limit is determined by taking the greater of two values: the first is a fixed value of 4 MJ/m2.annum, and the second is calculated using a formula. This formula incorporates two variables: the total annual heating degree hours specific to the building's location, and an area adjustment factor for the heating load limit, which can be obtained from Table S44C2 based on the total area of the habitable room.
S44C3
Cooling load limit
New for 2022
S44C3
Cooling load limit
New for 2022
- = the cooling load limit (MJ/m2.annum); and
- = the total annual cooling degree hours of the building location; and
- = the total annual dehumidification gram hours of the building location; and
- = the area adjustment factor for the cooling load limit, determined in accordance with Table S44C3.
Total area of the habitable rooms (AH) | Area adjustment factor (FC) |
---|---|
≤ 50 m2 | 1.34 |
> 50 m2 and ≤ 200 m2 | |
> 200 m2 and ≤ 1000 m2 | |
> 1000 m2 | 0.71 |
To detail the calculation of the cooling load limit of a space.
S44C3 describes how to calculate the cooling load limit of a space, also in MJ/m2.annum. The cooling load limit is calculated using a formula that incorporates several variables. These include the total annual cooling degree hours and the total annual dehumidification gram hours, both specific to the building's location. Additionally, the area adjustment factor for the cooling load limit is determined using Table S44C3.
S44C4
Thermal energy load limit
New for 2022
S44C4
Thermal energy load limit
New for 2022
- = the thermal energy load limit; and
- = the heating load limit; and
- = the cooling load limit; and
- = the annual average daily outdoor temperature range.
To detail the calculation of the thermal energy load limit of a space.
S44C4 outlines the calculation of the thermal energy load limit, which is also measured in MJ/m2.annum. This is calculated using a formula that considers both the heating and cooling load limits previously calculated, as well as the annual average daily outdoor temperature range. Each of these elements forms part of the formula stated in this provision for determining the thermal energy load limit for a space.
Using the calculation method in Specification 44 is only necessary when developing a Performance Solution that assesses compliance directly against J1P2 or H6P1.